A conventional machine 7 for making expandable slats is shown in FIG. 10 and generally includes a plurality of rollers which feed a fabric strip 71 and the two sides 73 of the strip are folded toward a center of the strip and the folded strip 71 is then rolled by two pressing rollers 75 so as to form a slat that can be expanded by pulling the two sides of the strip. However, the two sides are easily tilted when folding so that the adverse rate is so high that increases the manufacturing cost.
FIG. 11 shows another machine 8 which feeds two strips 81 by two rollers 82 and the two strips 81 are arranged overlapped to each other. Two sides 811, 811a of the two strips 81 are then securely connected to each other by using ultra-sonic waves. The two overlapped strips are then expandable to form the expandable slat 84. Nevertheless, the two strips 81 are restricted to have the same colors.
The present invention intends to provide a machine for making expandable two-color slats and the machine is able to make the expandable slots composed of two strips of different colors.